Broad objective I: A. To delineate the mechanisms by which double-helical RNA triggers the production of interferon proteins. B. To determine, in chemical and physical terms, how certain polybasic compounds "enhance" this function of RNA's. Broad Objective II: A. To determine the chemical relationships between interferon proteins, of different apparent molecular weights, which are produced by exposure of cells to natural (virus) and synthetic (e.g., rI.rC) interferon inducers. B. To purify the human interferons to homogeneity in preparation for development of an immunoassay.